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The non-rigid registration is one of the most important research areas for various medical image analysis tasks and applications. This paper proposed a novel non-rigid image registration algorithm based on the traditional local afine transformation model. In order to protect the image local detaiis and edges, it used an adaptive nonlinear regularization term which took into account the regional statistical intensity information and the magnitude characteristic of the Chebyshev low pass filter. In the framework of the multi-resolution layered refining and coarse-to-fine warping strategy, the proposed algorithm achieved good performance in the registration of mono-modality medical images with relative larger deformations and the fine registration of multi-modality images with intensity variations which couldn't be processed by traditional algorithms. The experimental results show that the proposed algorithm is effective for non-rigid medical image registration. [ABSTRACT FROM AUTHOR]

Novel cup–saucer–cage-shaped sandwich electride molecules calix[4]pyrrole…K3O+…e@CnFn−, (n = 8, 10, 14, 20, and 36) with an excess electron protected inside the CnFn cage are constructed theoretically. In the sandwich structures, the below calix[4]pyrrole cup pushes the valence electron of the sandwiched superalkali atom K3O saucer, forming an excess electron, which is further pulled and protected inside the above CnFn cage, thus an electron-transfer relay occurs. In particular, owing to the unusual electron transfer, an unusual and fortunate phenomenon is discovered that increasing the CnFn cage size enhances not only the nonlinear optical response (β0), but also the electron stability (VIP). Thus, a new strategy of simultaneously enhancing β0 and VIP values is found for the first time, namely by increasing the CnFn cage size in novel cup–saucer–cage-shaped sandwich electride molecules, with the excess electron protected inside the cage. [ABSTRACT FROM AUTHOR]

Aiming at the problem of highly saturated and nonlinear characteristics of the flux linkage, it is difficult to model and analyze switched reluctance motor(SRM) using traditional methods, the issues that how to acquiring SRM's flux linkage characteristics simply and effectively were studied. An experimental measurement method was proposed in this paper. The principles, circuits, and steps of the experiment were described in detail to build an experimental platform. A four-phase 8/6 pole SRM was measured to obtain the characteristics of flux linkage, and the acquried flux model was compared with the analytical model. The results indicate that the proposed method is simple, convenient and low cost, which (ran accurately obtain the flux linkage model of SRM. The proposed method is of great significance for simulation and control research of SRM. [ABSTRACT FROM AUTHOR]

In order to study the operation characteristics and speed control performance of switched reluctance motor(SRM), based on the principle and control methods of SRM, an experimental platform of four-phase 8/6 SRM was designed on the basis of the digital signal processor-- TMS320F2812. The principle and features of the hardware circuit as well as the function and process of the software program were introduced in detail. Finally, multifile experiments on SRM were done based on the developed experimental platform. The results indicate that the software and hardware design of the experimental platform is correct and rffective. Meanwhile, it is also proved that switched reluctance motor has excellent speed control performance under speed PID control. [ABSTRACT FROM AUTHOR]

How to generate a non-zero first hyperpolarizability for a centrosymmetric molecule is a challenging question. In this paper, an external (pump) electric field is used to make a centrosymmetric benzene molecule generate a non-zero value of the electric field induced first hyperpolarizability (β). This comes from the centrosymmetry breaking of electron cloud. Two interesting rules are exhibited. (1) β is anisotropic for different directional fields ( F, i = X, Y, Z). (2) The field dependence of β is a non-monotonic function, and an optimum external electric field causes the maximum value of β. The largest first hyperpolarizability β reaches the considerable level of 3.9 × 10 a.u. under F = 330 × 10 a.u. for benzene. The external electric field effects on non-centrosymmetric edge-modified graphene ribbon HN-(3,3)ZGNR-NO was also studied in this work. The first hyperpolarizability reaches as much as 2.1 × 10 a.u. under F = 600 × 10 a.u. for HN-(3,3)ZGNR-NO. We show that the external electric field can not only create a non-zero first hyperpolarizability for centrosymmetric molecule, but also remarkably enhance the first hyperpolarizability for a non-centrosymmetric molecule. [ABSTRACT FROM AUTHOR]

The effects of periodic and non-periodic chaotic mixing on the morphology development in the blending of polypropylene as dispersed phase and polyamide 6 as continuous phase in a 2D batch chaotic mixer were investigated with experimental and computational fluid dynamic (CFD) methods. The rotor motions were delivered in steady, periodic (sine waveform and square waveform), and non-periodic (recursive protocol (RP) and restricted random sequence (RRS)) manners. The mixing efficiency was evaluated with flow number, Poincare map, morphology, droplet size and its distribution. Compared with the sine waveform, RP waveform could eliminate the island structures which existed in the flow domains and its corresponding spatial stretching distribution was more uniform. The recursively generated flow using RP lead to higher mixing efficiency and smaller droplet size with narrow distribution. However, the performance of RRS was ordinary even worse due to its random sequence.© 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

The effect of agitation on the fluidization performance of a gas-solid fluidized bed with a frame impeller is experimentally and numerically investigated. A 3-D unsteady computational fluid dynamics method is used, combining a two-fluid model and the kinetic theory of granular flow. The rotation of the impeller is implemented with a multiple reference frame method. The numerical model is validated using experimental data of the bed pressure drop and pressure fluctuation. Although the minimum fluidizing velocity and bed pressure drop are independent of the impeller agitation, a sufficiently high agitation speed yields higher fluidization performance with reduced bubble diameters and internal circulations of particles. The fluidized bed can be divided into three zones: inlet zone where the gas distribution plays a major role, agitated fluidization zone where the impeller agitation has a positive effect on fluidization, and free fluidization zone where the impeller agitation has no effect on fluidization. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1066-1074, 2013 [ABSTRACT FROM AUTHOR]

The solid state polymerization (SSP) of poly(ethylene terephthalate) was studied experimentally over a wide range of pellet sizes and temperatures. A comprehensive model was developed. It considered polycondensation, degradation and polycondensation of vinyl end groups together with diffusion. The reaction rate constants, diffusivities and the corresponding activation energies were obtained through parameter identification using experimental data. The effects of the reaction temperature and pellet size on the SSP time were also investigated. A decrease in the particle size decreases the concentration of the vinyl end groups and narrows the concentration distribution of end groups inside poly(ethylene terephthalate) particles. A decrease in the size of pellets also favors diffusion. Nevertheless it is preferable that the size of pellets be between 1 and 2 mm because too small pellets bring about difficulties with preparation and handling. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

Abstract: A layer-by-layer (LBL) approach was used to assemble alternating layers of sodium alginate (ALG)/polyethyleneimine (PEI) on biaxially oriented poly(lactic acid) (BOPLA) films in order to produce bio-based all-polymer thin films with low gas permeability. Increasing the depositing of ALG and PEI from 0 to 30 layers results in large thickness variations (from 0 to 3.92μm). After 30 ALG/PEI layers are deposited, the resulting assembly has an OTR of 1.22cm3/(m2 dayatm). When multiplied by thickness, the resulting oxygen permeability (OP) is found to be less than 3.8×10−17 cm3 cm/cm2 sPa, which is almost 3 orders of magnitude lower than that of uncoated BOPLA film (1.8×10−14 cm3 cm/cm2 sPa). At the same time, the resulting multilayer-coated BOPLA films maintain high optical clarity and tensile properties. This unique barrier thin film has become a promising alternative to non-biodegradable synthetic food packaging materials. [Copyright &y& Elsevier]

Abstract: X-Z inverted pendulum not only has nonminimum phase and underactuated performance that normal inverted pendulum has, but also has more control freedoms. The equivalence relationship between X-Z inverted pendulum and planar vertical takeoff and landing (PVTOL) aircraft is found through definite states transformation. The saturated nonlinear control method original from the control method of PVTOL aircraft is used to the stabilization control of the X-Z inverted pendulum based on the equivalence relationship between them. The stabilization method is compared with the PID (Proportion integration differentiation) control through simulation. And this proofs the effectiveness of the stabilization method. [Copyright &y& Elsevier]

The influence of agitation of a frame impeller on thefluidizationperformance of Geldart D particles is experimentally and numericallystudied in a gas–solid stirred fluidized bed, using a three-dimensional(3D) unsteady computational fluid dynamics (CFD) simulation. The bedpressure drops obtained from simulations are in reasonable agreementwith those measured with pressure transducers, which validates theCFD models. The experimental results of the pressure fluctuation andthe simulated ones of the solid volume fraction distribution showthat Geldart D particles can perform homogeneous fluidization in thepresence of the impeller. The homogeneous fluidization regime expandsas the minimum bubbling velocity increases with the agitation speedwhile the minimum fluidizing velocity remains unaffected. In addition,the uniformity of particle velocities that are distributed in theentire fluidized bed is also improved by the agitation of the frameimpeller. [ABSTRACT FROM AUTHOR]

Abstract: X–Z inverted pendulum is a new kind of inverted pendulum which can move with the combination of the vertical and horizontal forces. Through a new transformation, the X–Z inverted pendulum is decomposed into three simple models. Based on the simple models, sliding-mode control is applied to stabilization and tracking control of the inverted pendulum. The performance of the sliding mode control is compared with that of the PID control. Simulation results show that the design scheme of sliding-mode control is effective for the stabilization and tracking control of the X–Z inverted pendulum. [Copyright &y& Elsevier]

Abstract: The dissipative particle dynamics (DPD) is used to study the compatibilizing process of an immiscible polymer blend using a graft copolymer as a compatibilizer. Polystyrene (PS) and polyamide 6 (PA6) are chosen as the polymer components of the blend. The graft copolymer is composed of PS as the backbone and PA6 as the grafts. Mesoscale morphology, density distribution, end-to-end distance of PA6 and interfacial tension are investigated. Simulations show that the presence of a graft copolymer contributes to the formation of finer and more uniform dispersed domains by preventing them from collision and coalescence. In the presence of a graft copolymer, the density distribution is more uniform and the dynamic equilibrium of the blend morphology is reached more rapidly. For a given backbone and number of grafts per backbone, the compatibilizing efficiency of the graft copolymer first increases with increasing graft length. However, when the graft length exceeds a certain value, it starts decreasing. [Copyright &y& Elsevier]

Abstract: Micromixing of viscous systems in a stirred-tank reactor with Rushton turbine is investigated numerically. It is characterized by the product selectivity of parallel competitive reactions. Flow fields inside the reactor are determined by the Reynolds Stress Model (RSM). A computational fluid dynamics (CFD) method combining the standard E model and Finite-Rate/Eddy-Dissipation (FR/ED) model is implemented and is validated using experimental data in the literature. The simulations show that a higher agitation speed, a lower fluid viscosity and/or a feeding location closer to the discharge area of the impeller favor micromixing and the reaction rate. The trajectory of the reaction plume also influences the micromixing performance. The value of the FR/ED model parameter determined by lab-scale experiments decreases with increasing fluid viscosity. However, it is little affected by the agitation speed. These results provide useful guidelines for the scale-up of industrial reactors with complex chemical reactions. [Copyright &y& Elsevier]